University of Alabama junior center William Vlachos started to notice a change about a week ago. It wasn't like someone flipped a mental switch so much, but the defense clearly wasn't happy with its first-half performance at Arkansas.

In the long run, those struggles may have been just what the young unit needed.

"They came with it," he said of the subsequent practices. "And they came with it this week."

Welcome to the sixth week of the regular season and things look a whole lot different than the opener against San Jose State or even throwback Saturday with Joe Paterno and Penn State. The meat of the schedule is at hand, with Southeastern Conference opponents week in and week out and the grind takes a toll.

Yet you hardly would have known it against the No. 7 Gators last Saturday, a rematch of the last two SEC Championship Games that ended up a 31-6 blowout.

"We knew we had to hit them in the mouth early," junior nose guard Josh Chapman said.

While there seems to be hardly any doubt that No.1 Alabama the best team in the country, everyone also knew coming into the fall that the defense would be a work in progress, particularly the secondary. You just don't lose nearly everyone except safety Mark Barron and expect no drop-off, especially executing a system as complex as Nick Saban's.

In that respect, free safety Robert Lester, who is in his third year on the Capstone, and second-year cornerback Dre Kirkpatrick, have been essential -- and enough can't be said about Barron's ability to lead. Without any of them the first five games might have been very different, perhaps a nightmare for the newcomers.

Alabama's ability to reach the next level, though, will depend on the front seven, after coaches sort of used the first three games as a preseason to see what they had. Concerns in the run defense led to changes: Enter sophomore Nico Johnson at weakside, freshman C.J. Mosley on passing down and everyone's roles were tweaked.

"I think the combination of those guys continuing to flourish in those roles will be important for us," Saban said. "Nico has done a good job for us all year."

That is until Florida, when sparked by Johnson's interception in the end zone things started to click together.

The hits were ferocious. The intensity was there. The swagger was back.

"Tremendous, they were swarming," junior running back Mark Ingram said. "They were relentless out there."

That was what fans and players hoped/envisioned, the same attacking style as last year's national championship unit only younger, faster and possibly more physical overall. Critics wondering from afar how claims the Crimson Tide might be even more talented could possibly be true finally saw it for themselves.

Now step back take a look at the big picture.

While finding its way Alabama has given up a total of three touchdowns, none in the second half and zero at home. It's second in the SEC with 13 forced turnovers including seven the past two games against top 10 opponents.

The Crimson Tide has created five turnovers in the red zone (inside the 20), while giving up just two touchdowns.

It's fifth nationally in third-down defense (18-of-69, 26.1 percent).

The impressive streaks of not allowing more than 21 points or a 100-yard rusher have reached 18 and 39, respectively.

And the young unit is only beginning to figure out how good it could be.

"Usually when you watch a team, the more you watch them, the more you see the weaknesses or the possibilities of their liabilities where you might attack them," CBS analyst Gary Danielson said this week. "The more I've watched Alabama, the more I've become impressed with their lack of weaknesses. They're very balanced at every level on offense and defense. Usually I have the opposite feeling when I watch a team. I watch them and I watch them and I say 'This guy's not as good as the hype.' This Alabama team, the more I watch them the more I say, 'Gosh, this group is good.' This defensive line is good. These outside linebackers are good. These safeties are good. These tight ends are good. It's kind of unique for me. I haven't seen a lot of teams that way.

"The last team I ever saw like this where the more I watched them, the better they got, was the 2002 Ohio State team that won the national championship."

This isn't to say that Alabama is going to survive the brutal schedule unscathed or won't have numerous obstacles to overcome. In reality, things will only get tougher, especially with every opponent having extra time to prepare with byes the preceding week - prompting Ole Miss coach Houston Nutt to say that "everybody should have an open date against Alabama because they're so good."

However, this defense has the potential to be something special. It has eight, possibly nine more games to get there.